Heart valve locking ring



FIG. 1 is a cross-sectional view of a heart valve locking ring, taken along line 1--1 of FIG. 3, with the broken line showing of the heart valve and cloth wrap being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a perspective view of the heart valve locking ring;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a side elevational view thereof. 

The ornamental design for a heart valve locking ring, as shown and described. 